Laminated films are widely used for packaging applications. The choice of substrate depends, at least in part, on the functional requirements (e.g., thermal stability, barrier, abuse resistance, and/or sealing) for the end use. Alternatively, package aesthetics (e.g., high gloss, transparency, and/or decorative printing) may impact the choice of substrate. A significant part of the packaging market uses glossy films as external layers for laminated packages in order to increase impact on the consumer. For several applications, the use of metalized films is also used due to both the appearance and barrier properties offered by such films.
Typical metalized substrates include polypropylene (PP), biaxially oriented polypropylene (BOPP), and polyethylene terephthalate (PET). Polyethylene-based films generally are not used as substrates for metallized films due to their poor metal adhesion and bond strength. Rather, polyethylene-based layers or films are generally used as internal substrates and require the addition of migratory slip agents to reduce the coefficient of friction. The addition of migratory slip is known to reduce even further the adhesion of metal on the polyethylene-based film or layer surface.